440 906 heads: Oil pooling top back side of head

[Red_Rocket_1965]

Hey guys, I have 906 cast iron heads and the old cork valve cover gaskets were getting pretty ratty so I thought I’d try the Moroso blue rubber gaskets…they leaked like crazy on both sides and I attributed that to the imperfections of the cast iron mating surface. So I’m back to a new set of Felpro cork gaskets and I also am having a hard time with leaks especially passenger side rear in the vicinity of #8….seeping out onto and down the headers - a topic that has been covered a million times. I applied some Permatex #2 so hopefully that problem is solved (I know there are dozens of possible solutions for this).

The main question is it normal to have so much oil pooled up around the #8 valves? When it’s running and oil is flowing I’m guessing it’s one of the the main reasons it’s leaking back there…there doesn’t seem to be any way the oil can drain back down…

The #8 spark plug also has some oil on it after it sits for a while - symptom of a bad valve guide seal?

 

[Geoff 2]

Yup, normal.

 

[Kern Dog]

I had a set of the Moroso blue gaskets and they leaked as if I had no gaskets at all. They decorate the wall now.

 

[WileE]

 

[1967coronet]

Make sure your valve cover edge / flange does not contact the header flange.

 

[Armyvet25]

View attachment 1862394

I have a love hate relationship with this stuff, used it for over 45 yrs, great product, but you have to literally shed your skin to get it off, I swear Jet fuel won't remove it

 

[ckessel]

I put some fresh gaskets, Fel Pro fiber type, on my MP cast covers. Leaked like a mofo from around the lower bolts. It seems that there is a gap on the backside where oil collects and then comes out. Next time I have them off, got the sealed up for now around those holes, I'll get them stuck to the covers but fill in those open areas on the backside before putting them back on. Caulk in the gaps!

 

[BSB67]

The main question is it normal to have so much oil pooled up around the #8 valves?

Yes

When it’s running and oil is flowing I’m guessing it’s one of the the main reasons it’s leaking back there…there doesn’t seem to be any way the oil can drain back down…

Right

The #8 spark plug also has some oil on it after it sits for a while - symptom of a bad valve guide seal?

Maybe.

 

[WileE]

I have a love hate relationship with this stuff, used it for over 45 yrs, great product, but you have to literally shed your skin to get it off, I swear Jet fuel won't remove it

If you know how to use it, you don't have leaks. I learned that over 50 years ago. When you have to do a job on a customers car, you can't give a job back that leaks. Yet everyone tries all these other remedies that don't work. {yawn}

 

[Mr. Mike]

During their life dealers took care of oil leaked by tightening the rocker cover bols rather than replacing gaskets, backyard mechanics did likewise.
Check the cover flange with a straight edge and gently hammer flat.
The get those rocker cover reenforcemets GM uses.

 

[Red_Rocket_1965]

Forgot to mention I’m running the Mopar cast aluminum covers. I used Permatex 2 to seal them and hopefully isn’t to hard to get it off since it doesn’t fully harden…

 

[coloradodave]

According to the packaging, the Moroso Silicone/Metal reinforced gaskets are designed for aluminum heads and cast valve covers, where you have two flat, machined surfaces to seal...

 

[Red_Rocket_1965]

Yep that was clear when I started it…should’ve read first…gonna hang onto them though…eventually I’ll get some nice aluminum heads to keep them company…

 

[Kern Dog]

According to the packaging, the Moroso Silicone/Metal reinforced gaskets are designed for aluminum heads and cast valve covers, where you have two flat, machined surfaces to seal...

Thanks. I had Edelbrock heads and MP cast aluminum valve covers and yeah....still had leaks.

 

[6PKRTSE]

The MP cast covers are notorious for leaks. I have had a few issues with rocker cover gasket leakage on a 3 different cars in recent years. No matter what gaskets, sealer or covers were used. I tried tightening to the point I had some threads that were pulling out. I had the most luck with using a bottoming tap and tapping the threads to the bottom of each hole and the using 1/4-20 studs with hex nuts and larger o.d. washers for more clamping force. Worked all 3 times on both sides to seal each car.

 

[Red_Rocket_1965]

The MP cast covers are notorious for leaks. I have had a few issues with rocker cover gasket leakage on a 3 different cars in recent years. No matter what gaskets, sealer or covers were used. I tried tightening to the point I had some threads that were pulling out. I had the most luck with using a bottoming tap and tapping the threads to the bottom of each hole and the using 1/4-20 studs with hex nuts and larger o.d. washers for more clamping force. Worked all 3 times on both sides to seal each car.

Are they just not flat or inconsistent? Do they work well on a machined head?

 

[Red_Rocket_1965]

Yes


Right


Maybe.

Seriously love your brevity by the way!

 

[Geoff 2]

[1] Use re-usable gaskets.
[2] Silicon the gasket to the valve cover & place on a flat surface for silicon to set [ kitchen table?]
[3] You have now eliminated 50% of the possible leakage area...

 

[BSB67]

Seriously love your brevity by the way!

Almost none of the responses speak to your questions. Thought I’d check the box.

 

[6PKRTSE]

Are they just not flat or inconsistent? Do they work well on a machined head?

Just like chrome covers, just too smooth of a surface. I roughed mine up with some sandpaper sheets on a surface plate. A flat board file with sandpaper will work just as well.